What then is the deeper distinction drawn by Christianity? What is the essential difference between the Christian and the not-a-Christian, between the spiritual beauty and the moral beauty? It is the distinction between the Organic and the Inorganic. Moral beauty is the product of the natural man, spiritual beauty of the spiritual man. And these two, according to the law of Biogenesis, are separated from one another by the deepest line known to Science. This Law is at once the foundation of Biology and of Spiritual religion. And the whole fabric of Christianity falls into confusion if we attempt to ignore it. The Law of Biogenesis, in fact, is to be regarded as the equivalent in biology of the First Law of motion in physics: _Every body continues in its state of rest or of uniform motion in a straight line, except in so far as it is compelled by force to change that state._ The first Law of biology is: That which is Mineral is Mineral; that which is Flesh is Flesh; that which is Spirit is Spirit. The mineral remains in the inorganic world until it is seized upon by a something called Life outside the inorganic world; the natural man remains the natural man, until a Spiritual Life from without the natural life seizes upon him, regenerates him, changes him into a spiritual man. The peril of the illustration from the law of motion will not be felt at least by those who appreciate the distinction between Physics and biology, between Energy and Life. The change of state here is not as in physics a mere change of direction, the affections directed to a new object, the will into a new channel. The change involves all this, but is something deeper. It is a change of nature, a regeneration, a passing from death into life. Hence relatively to this higher life the natural life is no longer Life, but Death, and the natural man from the standpoint of Christianity is dead. Whatever assent the mind may give to this proposition, however much it has been overlooked in the past, however it compares with casual observation, it is certain that the Founder of the Christian religion intended this to be the keystone of Christianity. In the proposition _That which is flesh is flesh, and that which is spirit is spirit_, Christ formulates the first law of biological religion, and lays the basis for a final classification. He divides men into two classes, the living and the not-living. And Paul afterward carries out the classification consistently, making his entire system depend on it, and throughout arranging men, on the one hand as {pneumatikos}--spiritual, on the other as {psychikos}--carnal, in terms of Christ's distinction.
Suppose now it be granted for a moment that the character of the not-a-Christian is as beautiful as that of the Christian. This is simply to say that the crystal is as beautiful as the organism. One is quite entitled to hold this; but what he is not entitled to hold is that both in the same sense are living. _He that hath the Son hath Life, and he that hath not the Son of God hath not Life._ And in the face of this law, no other conclusion is possible than that that which is flesh remains flesh. No matter how great the development of beauty, that which is flesh is withal flesh. The elaborateness or the perfection of the moral development in any given instance can do nothing to break down this distinction. Man is a moral animal, and can, and ought to, arrive at great natural beauty of character. But this is simply to obey the law of his nature--the law of his flesh; and no progress along that line can project him into the spiritual sphere. If any one choose to claim that the mineral beauty, the fleshly beauty, the natural moral beauty, is all he covets, he is entitled to his claim. To be good and true, pure and benevolent in the moral sphere, are high and, so far, legitimate objects of life. If he deliberately stop here, he is at liberty to do so. But what he is not entitled to do is to call himself a Christian, or to claim to discharge the functions peculiar to the Christian life. His morality is mere crystallization, the crystallizing forces having had fair play in his development. But these forces have no more touched the sphere of Christianity than the frost on the window-pane can do more than simulate the external forms of life. And if he considers that the high development to which he has reached may pass by an insensible transition into spirituality, or that his moral nature of itself may flash into the flame of regenerate Life, he has to be reminded that in spite of the apparent connection of these things from one standpoint, from another there is none at all, or none discoverable by us. On the one hand, there being no such thing as Spontaneous Generation, his moral nature, however it may encourage it, cannot generate Life; while, on the other, his high organization can never in itself result in Life, Life being always the cause of organization and never the effect of it.